RAM disappearing on my 2008 Mac Pro

Discussion in 'Mac Pro' started by codemonkey86, Dec 13, 2009.

  1. codemonkey86 macrumors newbie

    Apr 6, 2009
    I have an octo 3.2 GHz 2008 Mac Pro. I have 14 gigs of ram(6x 2gig, 2x 1gig sticks) and they are in the correct order/positions/pairings. My machine would properly show me as having 14gigs of ram for the last 9 months that I've had it however I recently installed windows 7 to one of the hard drives in my machine which proceeded to show me as having 12gigs of ram. When I would go back to OSX it changed to show me as having 12gigs of ram just as Win7 did. When I unplugged all the extra 2gig sticks I had purchased from OWC and powered on, then off and reinstalled the ram, I got the 14gigs to show again in OSX. However, as soon as I went back to Win7 and then back to OSX I was down to 12 gigs. Does anyone else have this issue or know a solution? Any assistance would be greatly appreciated as I am out of ideas and am tired of opening my machine up over and over again.
  2. chaos86 macrumors 65816


    Sep 11, 2003
    Microsoft is stealing from Apple again.

    I don't have a real answer.
  3. dcpmark macrumors 6502a

    Oct 20, 2009
    What are you using to access Windows 7, Parallels, Fusion? It's my understanding that one of these apps (can't remember which one) takes the RAM it needs and doesn't give it back until you delete the VM.
  4. codemonkey86 thread starter macrumors newbie

    Apr 6, 2009
    I'm just using bootcamp, not vm or fusion. i can get the ram back by pulling the sticks out and reinstalling them. I then get all 14 gigs until I jump into Win7
  5. Luis Ortega macrumors 6502a

    May 10, 2007
    Fetcham Surrey UK
    My problem was similar but not identical.
    After returning home from vacation, I started my Mac Pro and the ram amount was wrong.
    I cleaned the Mac Pro and when I reassembled the ram risers and modules, I started getting all sorts of wrong ram amounts reported.
    I kept taking them out and carefully cleaning the contacts and slots on the risers and on the motherboard and eventually the ram amount reported normally.
    It might just be a little bit of dust or incorrectly seated modules rather than anything to do with the windows 7 install.
  6. codemonkey86 thread starter macrumors newbie

    Apr 6, 2009
    Thats what I thought too, however after reassembling the RAM and getting back to 14 gigs I can't get it to disappear and it can stay for days(avoided Win7 for a few days). However I can trigger the change to 12 gigs simply by booting into Win7. As far as I have been able to tell booting into Win7 causes one of my pairs of 2 gig sticks to show as 1 gig sticks(system Profiler).
  7. 666sheep macrumors 68040


    Dec 7, 2009
    I think that the problem is somewhere in Boot Camp drivers. They are not certified by Apple to work with W7. Maybe this issue will gone when Apple will release new version of these drivers?
  8. macuserx86 macrumors 6502a


    Jun 12, 2006
    I had RAM problems like this that I was able to cure (so far) by re-seating the graphics card and RAM. Odd I know, but when you're troubleshooting, it's better to try everything. :D
  9. MRU Suspended


    Aug 23, 2005
    If bootcamp is reporting wrong amount, it should not affect OSX if it was merely a bootcamp / driver issue.

    Do you get any errors under memory in system profiler? Or is it all reporting as ok?
  10. Luis Ortega macrumors 6502a

    May 10, 2007
    Fetcham Surrey UK
    I also have win 7 (32 bit) on bootcamp on my mac pro but the win 7 is on a separate hard drive, and I have not been able to replicate your issue.
    I do know that in win 7 it only sees 3 of my 16 gb of ram, but it always goes back to showing 16 gb when I return to osx.
  11. codemonkey86 thread starter macrumors newbie

    Apr 6, 2009
    32bit is capped at 4gigs of RAM however Windows tends to show what is available and "hides" the rest saved for the system such as in your case you see 3gigs when in reality 4 are being used. I am running 64bit Win7 which along with OSX shows 12gigs of RAM(14 gigs in OSX only after opening the case up and playing around)

    Attached is a screenshot of my sys profiler. It shows 2 of my 2 gig sticks as being 1 gig sticks. I get this to show them as 2 gig sticks as it should and the 14 total gigs only after opening my case and going through what I outlined in my initial post.

    Attached Files:

  12. Earl Urly macrumors regular

    Jul 11, 2004
    Sell the OWC sticks on ebay and get them from somewhere more trustworthy like Crucial or NewEgg
  13. xraydoc macrumors demi-god


    Oct 9, 2005
    I vote for EFI error.

    Can you replicate the issue with Vista 64 bit?

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